Safety monitoring and shut down means for internal combustion engines, compressors and other stationary power equipment of great cost is essential. The prior art has proposed a variety of systems and devices to deal with the problem and one example of the patented prior art is U.S. Pat. No. 3,746,926 . This patent discloses a normally continuously energized magnetic control switch and visual indicator element for use as part of a safety indicating and shut down system for engines and the like, and responsive to malfunction or failure of such operational components as fuel supply means, air shut off solenoid, ignition means, lubrication supply and the like.
The main objective of the present invention is to improve on the efficiency and reliability of the prior art control, monitoring and automatic shut down means for engines and other power equipment by utilization of basically the same magnetic switch disclosed in the aforementioned patent in conjunction with a novel arrangement of safety switches which assures a fault-sensitive and fail-safe system of operation and overall increased reliability of the system. In comparable prior art arrangements, it frequently happens that, because of heavy vibration induced by the power equipment, a wire or wires connected with the safety switch may loosen or become disconnected thereby rendering the costly equipment unprotected when a malfunction of some vital control or operational component occurs. The present invention completely overcomes this difficulty by providing a fault-sensitive control circuit which will sense such wiring separations or other circuitry faults in addition to visually indicating a malfunction of any one equipment operational component and responding automatically to such malfunction by shutting down the equipment.
Other features and advantages of the invention will become apparent during the course of the following detailed description.